You are about to see the COOLEST EXPERIMENT I’ve ever done. If you like growing things, watching things grow, enjoy gardening, know someone that works with children (Teacher, Counselor, Home Schooling)..or even if you simply enjoy eating the freshest vegetables possible…this is a fantastic experiment.
What you are looking at is Sub Irrigation Planting, or SIP’s for short. In sub irrigation planting, plants get watered from the bottom up by drawing water from a reservoir.
How does Sub Irrigation Planting Work? Instead of the traditional method of watering from the top down, Sub Irrigation Planting uses a water filled reservoir along with a medium density media (“Soil”) to “Wick” the water upwards. As the media becomes saturated, any excess goes back into the reservoir. This constant movement of water keeps the growing area hydrated at all times, but because the media never gets overly saturated, the roots of the plants are not sitting in an anaerobic environment.
Why use Sub Irrigation Planting? The plants get the EXACT amount of water they need, the “Soil” (More on this later), stays damp but not wet around the roots, but only damp to dry on top, No wasting water due to evaporation, no fungus gnats, AND…. the plants grow faster and larger because they are in the PERFECT growing environment.
As you can see, I spent BIG MONEY to do this experiment. 😉 $1.50 for a 2 Litre soda bottle, plus a couple of dollars in peat and vermiculite and of course, some worm castings.
After securing my 2 litre bottle, I had to figure out a way to safely cut it. After trying many things, what I’ve found works best is using a Ginsu knife! These are the knives advertised as being able to cut cans, and just about anything else. Everyone should have one of these. The Ginsu knife goes cuts through plastic quickly, easily, and safely.
After cutting the bottle, you invert the bottom and use it as your reservoir.
Fill the reservoir with water.
The top part of the bottle is used to hold your “Soil” and seeds. I uses parenthesis around the word “soil” because with Sub Irrigation Planting, regular soil is not used. If you go into your yard and dig out some dirt, that dirt does not draw water properly. Clay soil will tend to stay too wet and harden into a clump. Sandy soil will not hold water well. What you want is a media that is fast draining, yet retains water so that it stays moist, not wet. What I have found is that peat moss, mixed with some compost, a handful of castings, and a little vermiculite is a perfect media for a SIP. I use 2 parts peat, 1 part compost, 1/4 part vermiculite, and 1/4 part castings. You can vary this depending on the height of your SIP. A taller unit will work better with some additional vermiculite.
Now comes the FUN! Invert the top of the bottle so that what was once the narrow top of the bottle now sits upside down in the reservoir. If you want to keep the reservoir clean, keep the screw lid on the bottle, and just drill a 1/4 inch hole so it can “SIP” from the reservoir. If you don’t care if the reservoir gets a little dirty, simply disgard the bottle cap altogether. A bit of the “Soil” will fall into the water, but it will soon form a plug in the neck of the bottle.
Your plants will sprout quickly in this environment, and once they take off…well…check this out!
This is even more gorgeous and larger in person than you can tell in the picture. I simply cut it off at the top, and it provided an entire bowl of salad. In a week or two, it should come back to produce another salad. Imagine how much fun your students can have with this!